Nuclear Fission Calculator

What is Nuclear Fission?

Imagine a very large, unstable atomic nucleus, like that of Uranium or Plutonium. Nuclear fission is the process where this heavy nucleus splits into two or more smaller, lighter nuclei. This splitting is usually triggered by hitting the heavy nucleus with a tiny particle called a neutron. When it splits, it releases a huge amount of energy and also more neutrons. This process is the basis for nuclear power and nuclear weapons.

Energy Release: The Power of E=mc²

The incredible amount of energy released during nuclear fission comes from a fundamental principle: mass-energy equivalence, famously described by Einstein's equation E=mc². Before fission, the heavy nucleus has a slightly greater mass than the combined mass of all the smaller fragments and neutrons produced after fission. This tiny bit of 'missing' mass, called the mass defect, is converted directly into energy. This energy appears mainly as:

• Kinetic energy (movement energy) of the fission fragments and released neutrons.
• Gamma rays (high-energy light).
• Later, from the radioactive decay of the fission products (beta and gamma radiation).

Mass Distribution: Uneven Splitting

When a heavy nucleus undergoes fission, it doesn't usually split into two equal halves. Instead, it typically breaks into two unequal fragments – one lighter and one heavier. This is known as asymmetric fission. For example, in the fission of Uranium-235, you often get one fragment with a mass number around 95 (like Strontium or Zirconium) and another around 140 (like Xenon or Barium). Understanding this mass distribution is important for predicting the types of radioactive waste produced and for designing nuclear reactors.

Chain Reactions: Self-Sustaining Fission

The key to harnessing nuclear fission is the chain reaction. When a heavy nucleus fissions, it not only releases energy but also 2 or 3 new neutrons. These new neutrons can then go on to hit other heavy nuclei, causing them to fission, releasing even more neutrons, and so on. This creates a self-sustaining chain of reactions.

• Criticality: If, on average, exactly one neutron from each fission causes another fission, the reaction is critical and proceeds at a steady rate (like in a nuclear power plant).
• Subcritical: If fewer than one neutron causes another fission, the reaction dies out.
• Supercritical: If more than one neutron causes another fission, the reaction grows rapidly and uncontrollably (like in an atomic bomb).
• Control: In nuclear reactors, control rods are used to absorb excess neutrons, keeping the chain reaction at a safe, critical level.

Applications of Nuclear Fission

Nuclear fission has revolutionized energy production and has several other significant applications:

• Nuclear Power Plants: The most well-known application, where controlled chain reactions generate heat to produce electricity, providing a large-scale, carbon-free energy source.
• Research Reactors: Used to study nuclear physics, material science, and to produce neutrons for various experiments.
• Medical Isotope Production: Fission products are used to create radioactive isotopes for medical diagnostics (e.g., PET scans) and cancer treatment.
• Nuclear Propulsion: Powers submarines and aircraft carriers, allowing them to operate for extended periods without refueling.
• Nuclear Weapons: Unfortunately, uncontrolled chain reactions are also the basis for atomic bombs.